On Dec 1, 2011, the Library of Congress introduced a new blog, Copyright Matters: Digitization and Public Access. The purpose of the blog is to keep the public informed about the effort to digitize copyright records prior to 1978. I could recap what the site says, but why not read it for yourself. You can also find more information about the project on the Copyright Website.
The January 6 post gives examples of what the copyright records look like. The card here is just one sample, be sure to check out the blog for more. Be sure to read the January 26 post on transfers and assignments as well. You will go away with a little background on copyright records.
The digitized catalogs of copyright entries can be accessed from the Internet Archive. They are almost 70% through with scanning the catalogs. Currently you will find issues from the 1920s through 1978.
This is exciting. One of the problems genealogists face is trying to determine if genealogies published before 1978 are still covered by copyright. As the catalogs and cards become accessible online we will be able to find out without sending a researcher to the Copyright office card file, or guessing and hoping that we’ve made the right choice.